The present invention relates in general to dental implants, and in particular to a new and useful dental implant hole guide arrangement which provides a dentist with an accurate guide to follow for drilling the critical initial pilot hole for a dental implant so that the hole is aligned on an acceptable axis in the patient's jaw bone, without endangering adjacent teeth.
Since 1981, dental root form implants have become a standard procedure for replacing missing teeth. Unlike other dental procedures such as crown and bridge work, root canals and the like, which utilize at least part of the original tooth as a foundation for the tooth replacement, implants require the drilling of holes directly into the bone of the jaw.
Although the dental implants have many benefits, particularly where a patient is missing teeth over large portions of the mouth, various complications can follow implant placement, especially to adjacent teeth. The bone may be overheated during implant surgery for example and this can devitalize an adjacent tooth. Endodontic lesions can also form which compromise the implant fixture by preventing integration of the bone around the fixture (Osseointegration) causing loss of the implant.
Another potentially more serious problem involves traumatic injury to the root of an adjacent tooth which is in the path of the hole drilled for the implant.
The case history of such a traumatic injury can be found in the inventor's article "Tooth Devitalization Via Implant Placement: A Case Report", Sussman, Periodontal Clinical Investigations, Vol. 20, No. 1, 1998, Northeastern Society of Periodontics, pp. 22-24.
FIG. 5 is a schematic diagram of an x-ray showing the cause of traumatic injury to a tooth 3 having a root 4 which was along the axis of a hole 5 drilled to receive an implant fixture 6. Tooth 3 was ultimately lost as was the implant 6 due to this traumatic injury.
Within the confines of the mouth, it is very difficult to accurately align a dental bur for drilling the crucial initial pilot hole of about 2 mm. in diameter. The pilot hole must be drilled along an acceptable axis into the jaw bone which both avoids any critical structures in the bone such as nerves, blood vessels and the like, but also avoids intersecting the root of an adjacent tooth which may not be apparent without x-rays. Even with x-rays, however, it is difficult for a dentist to accurately align the bur without some help.
One very complex and time consuming technique for properly aligning the initial implant hole for a patient is disclosed in U.S. Pat. No. 5,015,183 entitled LOCATING DEVICE AND METHOD OF PLACING A TOOTH IMPLANT. According to this method, a stent comprising a negative impression of a patient's teeth in the vicinity of the implant is taken. Multiple x-ray opaque strips are placed in the negative impression and an oblique x-ray is taken. This x-ray is used as a diagnostic tool for the patient's jaw structure to help plot the trajectory of an implant fixture in the jaw.
Once an acceptable initial implant hole is formed in the jaw, subsequent holes can be produced by using the initial hole as a guide. This is when multiple implants are to be installed. See, for example, U.S. Pat. No. 5,741,133 and U.S. Pat. No. 5,302,122. Other techniques and apparatuses for drilling holes in the jaw bone are disclosed in U.S. Pat. Nos. 4,787,848 and 4,998,881. A need remains, however, for a simple and effective tool which can be used particularly by general dentists to permit them to produce the initial pilot hole along an acceptable axis in a patient's jaw bone. Once the initial bore is made, it can be enlarged to the required final diameter, generally about 4 mm., using ever increasing bur sizes. Once the initial hole is drilled, the enlargements are easily made using the initial hole as the guide. The present invention provides a way of making that critical initial hole.